The biologically active upper shell of the Earth is called the soil cover. Its main quality is fertility. It determines its suitability for the cultivation of cultivated plants, providing food for the population of the planet. All this gives the soil a major role in the production of agricultural products.
Structure and properties
The soil cover of the Earth is a unique natural formation. For the life of human civilization, its importance is high. It is he who is the main source of food. Provides almost 98% of the resources for the population. The soil cover is also the place of human activity. Production is concentrated on it - both industrial and agricultural. This is where people live.
Soil and topsoil are very diverse. This is due to the fact that the rocks that form them are heterogeneous. Their mineral composition and technological parameters are responsible for this. It is on them that the ability of the layers of the earth to keep inown moisture. Also, the mineral composition is responsible for the predisposition to soil erosion. This indicator determines the rate of decomposition of organic matter in it. This gives the soil characteristics that affect the methods of land use.
Soil-forming rocks occupying the upper layers of the planet, depending on the intensity of the impact on them of processes - biochemical and biological, have created in different areas a soil cover that is different in productivity and fertility. Human activity also plays a major role in the formation of the Earth's upper layer.
Soil formation
Natural soil cover was formed from rocks that came to the earth's surface, under the influence of various factors. These are wind, atmospheric moisture, climate change, temperature fluctuations. Initially, their influence led to the fact that the rocks began to crack, turn into the so-called rukhlyak. Microorganisms began to settle on it, feeding on atmospheric nitrogen, carbon, and mineral compounds that they extracted from rocks.
The vital activity of microorganisms led to the fact that their secretions gradually destroyed rocks, changing their chemical composition. Subsequently, mosses and lichens began to settle in such places. After the end of their life cycle, microorganisms decomposed their remains, forming humus, which is the main organic matter containing nutrients important for plant life. The vital activity of the latterled to the complete destruction of rocks, starting their transformation into soil.
Growing plants, grass, formed deciduous litter, which, decomposing, released a significant amount of organic matter. This led to an increase in soil cover.
Soils with an optimal ratio of air permeability and moisture capacity include structures formed from rock fragments - fine-grained and small-lump. In them, the main part of the fractions has a diameter of 1 to 10 mm. It should also be noted that its parameters and properties depend on the characteristics of the original rock on which the soil was formed.
To get a complete picture, specialists carry out selective sections of the earth for further study. Their findings are of great importance for the implementation of agricultural activities.
Composition
The soil cover includes a set of macronutrients, among which nitrogen, iron, potassium, calcium, sulfur, and phosphorus predominate. It also contains trace elements: boron, manganese, molybdenum, zinc. All of them play a certain role in ensuring the life of plants. By their ratio in the soil, its chemical composition is determined.
The structure of the soil cover is a conglomerate consisting of 4 parts: living, gaseous, liquid, solid.
The hard part
Represents the main part of the soil. Its volume is from 80 to 97%. It prevails over the organic component, it is formed from structures that have arisendue to the long-term transformation of rocks. The hard part is particles of various sizes, which can include stones of considerable size, and microscopic particles in thousandths of a millimeter.
It is generally accepted that particles, the main part of which in the soil cover has a size of more than 3 mm, is a stony component. From 1 to 3 mm - gravel. From 0.5 to 1 mm - sand. From 0.05 mm to 0.001 - dust. Less than 0.001 mm - ill. One that has a particle size of less than 0.0001 mm is colloidal. Soils where particles with a diameter of less than 0.01 mm predominate are classified as clay. Those with a fraction size of 0.01 mm to 1 mm are sands.
The fractions indicated above, which determine the main characteristics of the mechanical composition of the soil, refer them to sand, loam, clay.
The main part of the substances necessary for plants is concentrated in fine clay fractions. Colloidal particles are the most valuable, since the microelements contained in them are optimally available to plants. As a result, silty, clay soil is considered the most fertile.
Particles that form sandy soils contain a significant amount of quartz, which does not provide nutrition to plants.
Liquid part
It is also called soil solution. It is water in which organic matter and minerals are dissolved. The earth always contains water. However, in different quantities. Its share ranges from tenths of a percent to 60%. The liquid part ensures the delivery of the minerals dissolved in it to the plants (roots).
Gas portion
Partgaseous is soil air. It is located in pores not filled with water. The main component is carbon dioxide. Atmospheric air, there is little oxygen in it. It also contains methane and other volatile organic compounds.
Live part
Represented by microorganisms, which include mycelium, algae, bacteria, representatives of the invertebrate family (mollusks, insects and their larvae, worms, other protozoa), burrowing vertebrates. Their habitat is the upper layers of the earth, the roots.
Physical properties
Soil cover is characterized by certain physical properties. These are moisture capacity, water permeability, duty cycle.
Moisture capacity refers to the ability of the soil to absorb and retain a certain amount of moisture. It is determined as a percentage of the soil mass in the dry state. Calculate in millimeters.
Water permeability - the ability of the soil cover to pass water. It is determined by the volume of water in millimeters that penetrates through its upper layer in a set period of time. This indicator is directly dependent on the type and composition of the soil.
Sandy, structureless, loose, has high water permeability. Structureless, clayey, poorly pass moisture. As a result, they are predisposed to the accumulation of water in the upper layers. Moisture is poorly absorbed, contributing to the occurrence of water erosion. The upper layers are usually more permeable than the deeper ones.
Duration ratio (porosity) - volumethe space that exists between the particles of the soil cover. It determines the mass of water that the earth can support.
Factors affecting soil conditions
Characteristics of the soil cover, its composition and properties are constantly subject to changes that occur under the influence of climate and human activities. So, after fertilizer is applied to it, it is saturated with nutrients that favorably affect plant growth, thereby changing its physical data.
Incorrect human exploitation of the soil, on the contrary, leads to negative changes, provoking the occurrence of erosion, waterlogging, salinization.
The soil cover improves its characteristics if there is an optimal combination of mineral and organic parts - humus, which tends to retain moisture with nutrients. Its lumpy, aggregated structure increases the level of aeration, carries out water infiltration, and increases workability.
Humus is formed due to the fact that organisms consume the retreat. At the same time, the mineral parts of the soil cover are mixed with humus, forming a favorable structure.
Fertility
The most important characteristic of soil cover is fertility. It denotes a set of properties that ensure the yield of agricultural cultivated plants.
Natural fertility is determined by a combination of the impact on the soil cover of regimes (water, air and thermal), reserves init nutrients.
The role of soil in the efficiency of the Earth's ecological systems is very high. It provides nutrition to plants located on its surface, water, stimulating their growth by supplying the necessary chemical elements. It is one of the main components in the implementation of photosynthesis.
Human role in land cover conservation
Mankind is faced with the task of ensuring the correct and efficient use of the land, increasing its fertility by ensuring optimal thermal, air, and water regimes. This is achieved, among other things, by the implementation of land reclamation measures and the application of fertilizers to the soil.
Irrational, improper use of land resources leads to the fact that fertility is reduced, the land is depleted. The destruction of the soil cover begins. Decreased plant yields. An increase in wind and water erosion of the soil is recorded. This leads to the fact that its upper, most valuable layers are carried out through the impact of wind and water on them.
Modern environmentalists are sounding the alarm about the fact that erosion has already caused irreparable damage to the soil of the planet. It, along with soil pollution with human waste products, has become one of the most dangerous factors threatening the Earth's ecology.
